Collaborators can't sort rows

edited 12/09/19 in Smartsheet Basics

I've been using Smartsheet for years, and this is the first time I've encountered this issue. I have a number of free collaborators in a shared space, all having access to 6 sheets. They all have the same permission level: Editor - Can Share. At first it was working fine, but then people started emailing me saying they can't sort the rows. Not only is sort greyed out for them, but other column options are as well. See the attached screenshot. What is going on? Why can't they sort rows? I even made one user an Admin and he still can't sort rows. I did send a request to Smartsheet support, but I'm hoping maybe someone here knows what's going on. No filters are applied and none of the columns are locked. Thanks!

can't sort.png